This invention relates generally to multisection telescoping rods and, more particularly, to telescoping measuring rods (e.g., leveling rods).
When the telescoping sections of a measuring rod are extended, it is important that they be rigidly held in coaxial alignment, with each section being firmly supported within the next larger section. Heretofore such stability has been achieved by sizing each section so that, when fully extended, a substantial portion of the section remains in the next larger section of the rod and has a close clearance fit therewith. While this construction has provided the necessary rod rigidity, the substantial amounts of friction generated in the close clearance fit areas as the sections are telescoped in and out has resulted in excessive wear of the rod sections and has made the sections rather difficult to extend and retract with respect to one another. The large area of close clearance fit has also increased the expense of the rods.
Reference may be made to U.S. Pat. Nos. 2,980,456 and 3,103,375 describing telescoping poles generally in the field of this invention.